When routing optical connections in large scale Dense Wavelength Division Multiplexed (DWDM) networks, the optical signals may be optically regenerated to overcome losses due to attenuation and distortion induced by long-haul fibers. Optical regenerators receive an incoming optical signal at an optical wavelength, convert the optical signal to an electrical signal, process the electrical signal, and then retransmit the processed signal (after it is converted back to an optical signal) at an outgoing optical wavelength. Thus, optical regenerators act as optical-electrical-optical (OEO) repeaters.
Due to the high data rates that are carried on DWDM networks, high speed electronics are needed for the OEO conversion performed in an optical regenerator. The high speed electronics are expensive and consequently make optical regenerators the most expensive component along the communications path. Therefore, their use should be minimized. Since such regenerators are not necessarily on the shortest physical path between the endpoints, the nodes need to consider all feasible paths in the network to find one that minimizes regenerator usage. As a result, approaches based on considering a predetermined number of shortest paths during the connection signaling phase will not necessarily minimize regenerator usage.